Margaret Thatcher with Kevin Keegan, left, and Emlyn Hughes, right, before the 1980 European Championship. Photograph: David Levenson/Getty Images/Hulton Archive

1 Transforming the City of London

Until the late 1970s, the Square Mile was a genteel all-male club dominated by pinstripe suits, public school accents and a culture of long lunches. Money was made at the Stock Exchange with effortless panache, as a coterie of licensed dealers acted on behalf of stockbroker firms with redolent names such as Quilter and Co.

The Big Bang blew the ancien regime apart. Within six months of Margaret Thatcher's election, exchange controls were lifted and foreign capital flooded into Britain. The deregulation of the Stock Exchange in 1986 was an invitation to the world's biggest beasts to enter the trading floor.

Traders began to send huge amounts of money fizzing around the world's financial networks. The towers of Canary Wharf rose silver and immaculate from the industrial desert of the former London Docklands. The capital began its journey to world financial domination.

The crash of five years ago cast a shadow on the free-for-all spirit that the Big Bang let rip. But Thatcher's deregulatory push created the new internationally focused City. For better and for worse, it hasn't looked back. At the start of this decade the financial sector was estimated to be worth £125.4bn, or 9.4%, in gross value to the UK economy.

2 Privatisation

As part of a famous television ad campaign from September 1986, an ordinary looking bloke is shown in a fictional village pub. Lost in thought, he almost knocks a passing postman from his bike. It turns out he is preoccupied with the news that he can buy shares in British Gas. After passing on the good news to the postie, he adds: "If you see Sid, tell him."

The age of Sid was not simply a PR myth. Initially there really was a popular scramble by ordinary folk to sign up to the "people's capitalism" and reap the rewards. Four million people applied for British Gas shares at 135p a pop with a minimum purchase of 100. Many then sold them almost immediately for a quick profit. In Thatcher's second term, Jaguar, British Telecom, BritOil and British Aerospace were also sold off. Later, British Steel, British Airways, BP, water and electricity would follow. Thatcher said that privatisation was a chance to give "power back to the people". In fact, as Robert Philpot, director of the Progress pressure group, wrote last week: "Now, in 2012, it's clear that the result of electricity privatisation was to take power away from the people. Small British shareholders have no influence over the overwhelmingly non-British owners of the firms that generate and distribute power in Britain."

3 The Saatchi and Saatchi effect

Saatchi and Saatchi's "Labour isn't working" political poster, apparently featuring a long dole queue (made up of actors), became perhaps the most famous in the nation's history. British electioneering was changed for ever.

4 The decline of the north

When Britain's first female prime minister was in her pomp, northern football fans travelling to away games in London would be taunted by home supporters waving wads of £10 and £20 notes. The brutal repartee of the terraces expressed a fundamental truth of the Thatcher period: the north suffered the worst of the deep recession and high unemployment of the early years; and it benefited least from the eventual boom of the late 1980s.

It would be wrong to say that Thatcher planned the decline of the north's most vital industries and sources of employment. In fact, northern England suffered precisely from the absence of a plan in Westminster.

In 1985, explaining why she believed regional planning in Britain was a non-starter, Thatcher said: "If we try to discourage development and economic growth in large parts of the south of England, in the hope that it will happen in the large cities in the north, we risk losing them altogether."

Left to its own devices, the British economy rebalanced irrevocably to the south. Employment in the manufacturing industry, vital to the north's wellbeing, slumped, falling from 7.1 million in 1979 to 4.4m in 1993. Services and the booming City eventually took up much of the economic slack, but the good times were happening in the south.

5 A diminished role for trades unions

Thatcher came to power ready to take on the the National Union of Mineworkers, which had humiliated her Tory predecessor, Edward Heath, during the 1970s.

The miners' strike of 1984-85 allowed her to destroy the power of the NUM and institute a series of legal obstacles to industrial action – which she believed had bedevilled Britain in the 70s. Meanwhile, the decline in Britain's manufacturing industry, which Thatcher's government did little to reverse, destroyed the power bases of British trades unionism.

High unemployment and recession critically weakened the unions' bargaining power in the early- to mid-1980s. Since 1980, union membership in Britain has halved.

6 Open all hours

A backlash by the Christian right meant that Thatcher's shops bill, designed to allow Sunday trading, was voted down in 1986. It was her only defeat on an entire bill in the Commons. But the road to deregulation for shops and pubs had begun.

7 Shattering the postwar political consensus

After the second world war, British politics seemed to have come to a lasting settlement on the fundamentals of running the country. Both the Conservatives and Labour cherished the "mixed economy", balanced between public and private ownership. Pragmatism was the order of the day, as union leaders such as Jack Jones and Joe Gormley enjoyed beer and sandwiches at No 10. Economic policy was forged through achieving "tripartite consensus" between employers, unions and the government of the day.

The winter of discontent sounded the knell for that way of doing things. Thatcher arrived in power armed with the free-market philosophy of Ronald Reagan's adviser, Milton Friedman. "Managers must be allowed to manage" became the mantra, and a new style of politics was born.

8 The rise of power-dressing

The rise of the City of London, and its new money-focused ethos, spawned its own style. Designer labels came of age, suited to the new aspirational spirit. Actresses such as Joan Collins, (a Thatcher admirer) in the American glamour soaps Dallas and Dynasty, patented the look for would-be female power-dressers.

Shoulder-pads and sharply tailored suits ruled. Thatcher swore by her blue skirt suit, pearls and Asprey handbag, a look that was to influence powerful women from Hillary Clinton to Condoleezza Rice.

9 The Northern Ireland peace process

Among republicans in Northern Ireland, Thatcher is loathed for her intransigence during the Maze prison hunger strike of 1981, which led to the death of Bobby Sands. But four years later she appalled unionists by signing the Anglo-Irish agreement, which gave the Republic of Ireland a say in the affairs of the north, paving the way for the Good Friday peace agreement of 1998.

10 Education reforms

Thatcher's education secretary from 1986-89, Kenneth Baker, transformed the state school system, creating a proto-market that is being enthusiastically embraced and developed by one of his successors, Michael Gove. Baker insisted that attainment levels be made public, allowing a "league table" of schools to emerge. At the same time, he instructed schools to accept all applicants, local or otherwise, unless already full.

The choice agenda was born: parents could, in theory if not always in practice, decide which school their child would go to. Local authority control of education was also much-reduced by the Education Act of 1988, which gave autonomy over budgets and appointments to heads and school governors.

Gove has deepened that autonomy with his academy programme and added the further option of free schools.

11 Changing the way we watch football

Thatcher had no interest in football, despite occasional cringeworthy photo-ops, such as the pose outside No 10 with footballers Kevin Keegan and Emlyn Hughes before the 1980 European Championships. But when one of the worst incidents of football hooliganism broke out at a Luton-Millwall match in March 1985, she acted. The Football Spectators Act was passed in 1989, controversially making ID cards compulsory for fans.

After the Hillsborough disaster that year, in which 96 Liverpool fans died, the plan was never acted upon. Lord Taylor's Hillsborough inquiry recommended all-seater stadiums in English grounds. A revolution in who watched football and how they watched it was under way.

12 Inspiring a generation of Eurosceptics

When the European Economic Community began to develop far beyond a free-trade agreement, Thatcher's strident opposition to anything beyond a single market became a hallmark of her premiership. She inspired a generation of Eurosceptics and changed the chemistry of the Tory party. In much of the nation, fed on a diet of "Up yours, Delors!" style headlines and exposés of life aboard the "Brussels gravy-train", the mood gradually shifted from one of relative indifference to antipathy towards the EU.

13 Relations with Rupert Murdoch

Murdoch's Sun switched from backing Labour to the Tories for the 1979 election that launched Thatcher. The relationship became mutually beneficial from then on as she helped him create a power base that would be threatened only 30 years later, during the hacking inquiry.

In the early 1980s Murdoch launched a bid for the Times Group newspapers, which ordinarily would have been referred to the competition authorities, given his existing media holdings. Instead the deal went through on the nod after private meetings between Thatcher and Murdoch at Chequers.

Murdoch would later revolutionise the British media, defying the print unions and moving his News International media group to Wapping in an overnight coup de theatre. Thatcher backed him. According to cabinet minister Norman Fowler, any misgivings from colleagues or supporters would be met with the response: "Why are you so opposed to Rupert? He is going to get us in."

14 The revolution in home ownership

Britain was not always a country obsessed with house prices. But the Housing Act of 1980, which allowed council house tenants to buy their own homes, changed the face of home ownership in Britain. Many former local authority tenants paid less than £10,000 for homes that would be worth 10 times that a decade later. Over the next 30 years, this radical move towards "a nation of home-owners" led to a trail of unintended consequences.

A prolonged boom in house prices took place along with a chronic shortage of affordable housing – yet to be resolved by a series of governments – and the gradual emergence of a culture of debt, incurred on the presumption that the value of property would keep rising. In the private sector, rents soared.

In the first half of 1988 alone, house prices rose by 30%. On the back of the housing boom, much of Britain mortgaged itself up to the hilt and household debt reached record levels.

15 A new prestige for the armed forces

Winning the Falklands war in 1982 transformed Thatcher's standing in the opinion polls. Fighting it put the armed forces back on the centre stage for the first time since Suez. The Falklands revived the prestige of soldiering, as huge crowds gathered to wave off and welcome home the troops in Portsmouth. Later came the Gulf, Kosovo, Afghanistan and Iraq and the tributes to the fallen at Wootton Bassett.

16 Framing the debate

No one talks about abolishing private schools any more. Unilateral nuclear disarmament is not embraced by any of the three main political parties. In 1979, as Thatcher took power, the top rate of income tax was 83%. The ferocious battle this year over lowering the top rate of tax from 50% to 45% illustrates how far the debate on tax has shifted.

17 Transforming the Labour party

Losing three times to Thatcher led directly to the creation of New Labour and the emergence of Tony Blair as a leader who embraced her emphasis on choice, competition and an expanding role for the private sector in the economy. Following the crash of 2007, Labour under Ed Miliband has still to decide whether to make the break from that consensus.

18 The Tories and the Church of England

The observation that the Church of England amounts to "the Tory party at prayer" is thought to date to the 18th century. Thatcher's terms of office severely damaged that relationship, possibly beyond repair. The publication in 1985 of the C of E report Faith in the City, A Call to Action by Church and Nation, caused an almighty political row between the church and the Conservative party which has reverberated to the present day. Endorsed by Dr Robert Runcie, then archbishop of Canterbury, the document followed riots in Britain's inner cities. It was a cry of anguish over the dilapidated, alienated state of the inner cities, after years of recession, gloom and rising unemployment. Relations between the Tories and the established church have never truly recovered.

19 Transforming television

Thatcher saw the BBC licence fee as a tax imposed on television viewers irrespective of whether they wanted to watch BBC programmes or not. As prime minister, she believed that a leftwing bias permeated its coverage. During the Falklands war, rightwingers renamed the corporation the Stateless Persons Broadcasting Corporation – a dig at its refusal to describe British troops as "our" troops and Argentinian soldiers as "the enemy".

It was hoped that the 1990 Broadcasting Act would tame the institution, forcing it to outsource at least 25% of its production, and allowing new players into the market. But the legacy of the Thatcher era has been to drag the BBC into a perpetual culture war. And she helped create Channel 4 in 1982, probably not anticipating that it would popularise fiercely anti-establishment output.

20 Changing the world

Defeat in the Falklands war signalled the end of the road for Leopoldo Fortunato Galtieri Castelli, head of Argentina's last military dictatorship. Thatcher's friendship with Mikhail Gorbachev helped hasten the cold war to its end, as the economically moribund Soviet Union collapsed. However, her refusal to back sanctions on apartheid South Africa, and description of Nelson Mandela as a "terrorist", arguably delayed the fall of that regime.